Traditionally docking of watercrafts has been one of the more critical and difficult tasks to perform for a seaman. Especially when the weather conditions are harsh and the watercrafts or boats are relatively large.
A number of systems have been developed to ease docking of ships and boats.
In most cases manual docking control is required, at least for security reasons. In addition, docking is often a combination of automatic and manual docking procedures to control propulsion, thruster and possibly rudder devices. Efficient and intuitive docking control systems are therefore required. Bow and stern thrusters have for several years been used as a means for manoeuvring large and small watercraft in situations where the watercraft speed is too low to enable adequate rudder control. Particularly in connection with docking and setting off, or other low speed operations, thrusters are useful.
Bow and stern thrusters may be electrically- or hydraulically driven, and have traditionally been controlled by means of various joystick configurations mounted on the boat control panel, and operated by the person actually steering the boat.
In European patent publication EP1195320B1 a thruster control unit is shown. A boat shaped control is used to control bow and stern thrusters of the boat by pushing the control the intended way.
One of the main challenges related to manoeuvring a ship or a boat, is the complexity of operating different controls at a time for e.g. propulsion and thrust. Many seamen, especially those of leisure boats, are using their boats only occasionally, and may not be able to maintain the necessary skill level to be able to handle and understanding the meaning of multiple controls in a stressful docking situation.
Some integrated controls have been proposed for rotatable propulsion devices, where the joystick in addition to the two-dimensional fore, aft, port and starboard operations, also can be twisted left or right from a zero-position. The twist operation is then used for calculating individual direction and propulsion of the rotatable propulsion devices to make the boat pivot around its main vertical axis.